strykerhorse

Hey all. I am brand new to this site so i have a few questions:

-Will higher-level (Shimano Deore, etc) parts bolt on to my bike? (i.e. cranks, cassettes, disc brakes?) Right now I have all-original (Shimano Altus) parts besides the crank and front gears (Shimano Acera) which were replaced after an accident.
-This may be a painfully obvious question, but will a moderate gouge in one of the rear arms of the frame make that part of the frame more prone to snapping @ the gouge?

Thanks for any help you can give me!

_Nick